Prospective Evaluation of Predictive DNA Testing for Huntington's Disease in a Large German Center

Genetic diagnosis of individuals at risk of CADASIL: prospect for future therapeutic development

CADASIL is the most frequent hereditary cerebral small vessel disease worldwide. The disease is responsible for a slow and progressive accumulation of cerebral ischemic insults that lead to disabling cognitive and motor symptoms at late age. Although there is currently no cure for this condition, future therapies may concern subjects only at early stage of the disease. This will raise the question of the participation of asymptomatic carriers of pathogenic NOTCH3 gene mutation in future clinical trials, which will presuppose acceptance of presymptomatic genetic diagnosis. In this study, we questioned the population at risk of CADASIL who had not undergone a diagnostic procedure yet. Based on a questionnaire survey carried out by an independent team of sociologists, we analyzed what underlies the choice of people at risk to undergo or not to undergo a genetic test, and what could constitute the tipping point that could lead people who were initially not interested in their diagnosis to have recourse to it. Our results suggest that, far from being a simple, unequivocal path, the decision-making process leading to the choice of diagnosis is initially slowed down by the need to distance oneself from the disease so that it doesn't take over one's life, and then evolves under the influence of a complex tangle between advancing age, the presence of early symptoms, and the personal relationship with uncertainty. It cannot be ruled out that the real and imminent prospect of therapy may also modify responses to this type of survey.

Presymptomatic Testing for Huntington's Disease in Mexico: 28 Years of Experience

INTRODUCTION

Huntington's disease (HD) is a genetic neurodegenerative disorder with dominant inheritance. Our center in Mexico City has offered presymptomatic testing (PT) since 1995.

OBJECTIVE

To describe the main clinical and demographic characteristics of at-risk HD individuals who applied to the PT program, the reasons for seeking it, and the molecular results.

METHODS

A cross-sectional study was conducted with sociodemographic and clinical data of all PT applicants from 1995-2023. Reasons for seeking PT were assessed using a modified questionnaire. In addition, anxiety, and depressive symptoms before and after PT were evaluated with Beck's instruments; cognitive impairment (CI) was assessed with the Mini-Mental State Examination (MMSE) and molecular results.

RESULTS

214 people applied for PT (2.1% of the at-risk population identified in our center); 63% were women (mean age of 37.11 years). 204 (95.3%) were accepted and 190 received results. 70% indicated that the main reason for applying for PT was to inform their offspring about the risk of inheriting HD. Significant differences were observed in the reasons for seeking PT by age group. Although some subjects received treatment, Beck's instrument scores did not indicate special attention or pharmacological treatment. The MMSE showed probable CI in 20 subjects. Of those who received results, 37% were carriers of a full penetrance allele.

CONCLUSION

Our center has the only formal PT program for HD in Mexico. The reasons for seeking PT are varied and age-related. Although PT is offered to all subjects at risk for HD, uptake remains low.

Japanese women's reasons for accompaniment status to hereditary breast and ovarian cancer-focused genetic counseling

Genetic counselors routinely assess and understand clients' needs at the beginning of a session. Attending a genetic counseling session with or without companions is an objective sign that genetic counselors can easily notice. This study focused on clients' reasons for their accompaniment status for genetic counseling, which we categorize into attending with or without a companion(s). A questionnaire survey and interviews were conducted using snowball sampling, starting with the chief executive officer (CEO) of the Japanese hereditary breast and ovarian cancer (HBOC) support group. Of 32 participants, 19 continued with an in-depth interview after answering the questionnaire. Five themes were identified from the interview: (1) personal confidence, (2) decision-making style, (3) family members' habits and time availability, (4) considerations and conflicts with family members, and (5) healthcare provider's suggestion. Our data suggested that the clients expected their companion(s) to play certain roles. This indicates that the reasons of accompaniment status will be helpful for genetic counselors to understand both clients' and their families' motivations, personalities, habits, and psychosocial backgrounds. In a high-context culture such as that of Japan, accompaniment status may be a helpful sign to understand clients' true worries. In addition, some companions may be future clients in genetic counseling, due to the genetic nature of the disease. In conclusion, our study indicated that it is important for genetic counselors to record accompaniment status before the initial genetic counseling and to pay attention to its reasons at the beginning of the session, which may lead them to understand the client's psychosocial background to facilitate better client-centered genetic counseling.

Genetic counseling and testing practices for late-onset neurodegenerative disease: a systematic review

Objective

To understand contemporary genetic counseling and testing practices for late-onset neurodegenerative diseases (LONDs), and identify whether practices address the internationally accepted goals of genetic counseling: interpretation, counseling, education, and support.

Methods

Four databases were systematically searched for articles published from 2009 to 2020. Peer-reviewed research articles in English that reported research and clinical genetic counseling and testing practices for LONDs were included. A narrative synthesis was conducted to describe different practices and map genetic counseling activities to the goals. Risk of bias was assessed using the Qualsyst tool. The protocol was registered with PROSPERO (CRD42019121421).

Results

Sixty-one studies from 68 papers were included. Most papers focused on predictive testing (58/68) and Huntington’s disease (41/68). There was variation between papers in study design, study population, outcomes, interventions, and settings. Although there were commonalities, novel and inconsistent genetic counseling practices were identified. Eighteen papers addressed all four goals of genetic counseling.

Conclusion

Contemporary genetic counseling and testing practices for LONDs are varied and informed by regional differences and the presence of different health providers. A flexible, multidisciplinary, client- and family-centered care continues to emerge. As genetic testing becomes a routine part of care for patients (and their relatives), health providers must balance their limited time and resources with ensuring clients are safely and effectively counseled, and all four genetic counseling goals are addressed. Areas of further research include diagnostic and reproductive genetic counseling/testing practices, evaluations of novel approaches to care, and the role and use of different health providers in practice.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-021-10461-5.

Predictive Genetic Counseling for Neurodegenerative Diseases: Past, Present, and Future

Predictive genetic counseling for neurodegenerative diseases commenced with Huntington's disease (HD). Because the psychological issues and outcomes have been best studied in HD, the HD genetic counseling and testing protocol is still accepted as the gold standard for genetic counseling for these diseases. Yet, advances in genomic technology have produced an abundance of new information about the genetics of diseases such as Alzheimer's disease, frontotemporal dementia, amyotrophic lateral sclerosis, and Parkinson's disease. The resulting expansion of genetic tests together with the availability of direct-to-consumer testing and clinical trials for treatment of these diseases present new ethical and practical issues requiring modifications to the protocol for HD counseling and new demands on both physicians and genetic counselors. This work reviews the history of genetic counseling for neurodegenerative diseases, its current practice, and the future direction of genetic counseling for these conditions.

Psychological reactions to predictive genetic testing for Huntington's disease: A qualitative study

There is a lack of qualitative research investigating the experience of individuals at risk for Huntington's disease (HD) during the period prior to undergoing predictive testing, as well as their reaction to the test result. This secondary analysis study aimed to explore the experiences during the predictive testing process of individuals who had been or who were at risk for HD. For the primary study, in-depth semi-structured interviews were conducted, and data were analyzed using inductive thematic analysis. We employed the explorative qualitative design for this study, which involved 33 individuals who had been or who were at risk for HD. Results indicate that many had been anticipating the onset of the disease even before they knew their mutation status. Their choice of whether to get tested or not was influenced by personal, social, and practical factors. Whether the test result was positive or negative, coping with the test result was reported to be difficult. Participants with a mutation-negative result felt a need for more follow-up consultations than what they had received. Findings indicate that the decision to undergo predictive testing for HD was not only a personal choice, but was also influenced by both proximal and distant factors. Similar to individuals who tested positive for the mutation, individuals who tested negative for the mutation may need comprehensive follow-up to adapt to the reality of the test result.

Investigating the role of genetic counseling in neuromuscular disease considering life events

Genetic diagnoses are becoming a routine in the medical practice of neuromuscular diseases. Many diagnoses, however, can have an influence on relatives and family members and thus must be handled carefully by genetic counseling (GC). Here, we aimed to assess the purpose of undergoing GC to verify the utility of collaborations between clinical and genetic divisions. We investigated consecutive GC cases of neuromuscular disease and examined the role of GC. Our study included 102 cases who underwent GC in our hospital from July 2005 to March 2018: 86.3% were women and 45.1% were in their 30's. Disease explanation was the most common reason for attending GC (29.4%), followed by prenatal diagnosis (25.5%), pre-symptomatic diagnosis (17.6%), and carrier diagnosis (14.7%). Clients typically visited the hospital for GC when some kind of life event occurred, such as marriage, had a desire to bear a child, or a change in the condition of the proband. Clinicians should be conscious of such life events from the perspective of both the client and their relatives, and guide the GC at an appropriate time. Overall, the degree of recognition of genetic risk by clients differed; thus, it is important for GC to determine the status of each unique situation and respond individually.

On the personal utility of Alzheimer's disease-related biomarker testing in the research context

Many healthy volunteers choose to take part in Alzheimer's disease (AD) prevention studies because they want to know whether they will develop dementia-and what they can do to reduce their risk-and are therefore interested in learning the results of AD biomarker tests. Proponents of AD biomarker disclosure often refer to the personal utility of AD biomarkers, claiming that research participants will be able to use AD biomarker information for personal purposes, such as planning ahead or making important life decisions. In this paper, the claim that AD biomarkers have personal utility for asymptomatic individuals is critically assessed. It demonstrates that in the absence of clinical validity, AD biomarkers cannot have personal utility and do not serve research participants' autonomy. Over the next few years, many research groups will be confronted with participants' preferences to learn the results of AD biomarker tests. When researchers choose to make results available upon explicit request, they should ensure adequate information provision and education, notably on the uncertain clinical significance of AD biomarker information. Routine disclosure of AD biomarkers to cognitively unimpaired individuals in research settings cannot be justified with an appeal to the personal utility of AD biomarker information.